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Eight swine flu cases identified in U.S.
The most recent victim, a child, has recovered, as did the other seven victims, Dr. Richard Besser, acting director of the Centers for Disease Control and Prevention said Friday in a telephone news conference. Six of the eight U.S. cases were in San Diego and Imperial counties and two in Guadeloupe County, Texas.
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Swine flu? The plague? What's up in San Diego?U.S. victims or any common behaviors, Besser said, suggesting "that there has been transmission through several cycles" -- that is, there were several intermediaries who passed it among themselves before the virus reached the identified victims.
None of the American victims has had any contact with pigs and only one of them has traveled to Mexico recently, he said.
The Pan American Health Organization said Friday that there have so far been 854 cases of "influenza-like illness" in Mexico City, with 59 deaths. Another 24 cases with three deaths have occurred in San Luis Potosi, in central Mexico, and 24 cases with no deaths in Mexicali, near the U.S. border.
Friday afternoon, Mexico's Health Minister Jose Angel Cordova held a news conference at which he said the rate of deaths is slowing. He also said that there are no plans to close the borders because of the outbreak.
U.S. health experts noted, meanwhile, that deaths from influenza are common. In an average year in the United States, about 35,000 people die from the flu, and in bad years nearly twice that number. Such deaths are most often among the very young and the elderly. Most of the cases in Mexico, however, have been among people who were apparently young and healthy.
That is potentially alarming, experts said, because the 1918 influenza epidemic also struck the young and healthy.
Besser said CDC researchers had so far analyzed 14 samples from seriously ill Mexican patients, but only eight of them tested positive for swine flu. "I think we are safe in saying it is the same virus in Mexico and California," he said. The six cases that did not test positive might have been caused by other strains of flu, but "we can't say what they were," he said.
Canadian laboratories have confirmed 18 of the Mexican cases as swine flu and have found that 12 are genetically identical to the swine flu virus found in California, according to the Pan American Health Organization .
"It is really critically important that we learn more about what is going on in Mexico," Besser said. "Sorting out which of the cases are caused by swine flu is an important public health question. . . . There is much uncertainty, more than anyone would like."
The agency has not yet sent investigators into Mexico, "but I anticipate we will have folks there very soon," he said.
The World Health Organization said it is monitoring the situation closely and will probably send a research team to Mexico as well.
Besser said the agency was not calling for any travel restrictions to Mexico or to the affected areas in the U.S. "We're reminding travelers of our standard recommendations," such as washing your hands frequently and covering your mouth when you cough or sneeze. "If you are sick and have the flu, you should stay home and not get on a bus or airplane."
The new swine virus is unlike any that researchers have seen before. It appears to be a combination of segments from four different viruses from three continents, including a human segment, an avian segment and pig segments.
Epidemiologists are typically concerned about swine flu because the animals often play a crucial role in the creation of new flu strains. While viruses from birds are rarely transmitted among humans, bird and human viruses can mix in pigs, creating hybrids that retain the virulence of bird flus while gaining the ability to pass from human to human.
The U.S. suffered outbreaks of swine flu in 1976 and 1988, but both were limited in scope and spontaneously disappeared.
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